Project Abstract People with aphasia (PWA) and their families indicate that regaining the ability to converse with others is one of their greatest rehabilitation goals. Despite the critical importance of conversation in every facet of daily life, research-based language interventions aimed specifically at conversation do not exist. Critical to development of such intervention are relevant and reliable methods to measure change in language production at the conversation level. Thus, to meet this need, the broad, long-term the goals of this project are to determine which micro and macrolinguistic measures are reliable for use in measuring linguistic skills in conversation in PWA. Further, this research will provide knowledge required for appropriate clinical use of the measures (i.e., relationship of each measures in narrative and conversational discourse contexts) and for appropriate interpretation (i.e. understanding of functioning of healthy adults (HA) for three measures not expected to be at ceiling).The findings of this study will have public health impact by providing foundational knowledge needed for comprehensive assessment of aphasia that includes conversation-level discourse. Further, public health will be affected because the findings of this research will permit the much-needed development of relevant, effective treatment specifically directed to conversation, crucial to the health, well-being and recovery of independence in PWA. This research is situated directly within the scope of the NIDCD?s Strategic Plan for 2017-2021. The study will provide data meeting the need for research that extends the knowledge base in the understanding of normal function and dysfunction (aphasia) within the domain of a functional communication need (conversation), while providing foundational knowledge that can impact diagnosis, and treatment, and improve overall outcome for human communication, stated goals of the NIDCD. A group study design will be used to address: Specific Aim 1: Evaluate the test-retest stability of word- and utterance level discourse measures of micro and macrolinguistic skills and communicative success (CS) in PWA and HA during unstructured conversations with two unfamiliar Speech Language Pathologist partners experienced in working with PWA (SLP-Ps). Specific Aim 2: Evaluate presence and extent of significant between group differences for PWA and matched HA groups for three measures of informativeness, global cohesion and CS in conversation with an SLP-P. Specific Aim 3: Evaluate significance and extent of correlation of each measure in unstructured conversational discourse and structured narrative (story-telling via wordless picture book) in PWA. This research will be conducted in Dr. Lisa Edmonds? Aphasia Research and Bilingualism Lab at Teachers College, Columbia University, an environment providing space, equipment, an extensive research library, materials, and opportunity for intellectual dialogue. The proposed training plan is designed to provide experiences and support to the PI needed to further her development as an independent researcher.